Summary A factor for resistance to yellow rust in the Iranian spelt wheat accession 415 was found to be located on chromosome 1B, utilizing a monosomic series of TTspeltavar.saharense.Ditelosomic stocks of cv . Chinese Spring, were employed to verify the identity of the critical chromosome . The factor for resistance is most probably identical with the Yr10 allele which is also located on chromosome 113 . Moreover, the response of cv. Moro which carries Yr10 and accession 415 to 22 yellow rust races, representing a wide pathogenicity spectrum, was identical .